The inventive concepts described herein relate to semiconductor memories, and more particularly, to a nonvolatile memory device, to a memory system including a nonvolatile memory device, and to a method of controlling a memory system including a nonvolatile memory device.
Semiconductor memory devices may be volatile or nonvolatile. Volatile semiconductor memory devices are generally characterized by the loss of contents stored therein in a power-off state, whereas nonvolatile semiconductor memory devices are generally characterized by the retention of contents stored therein in a power-off state.
Flash memory is one example of a nonvolatile semiconductor memory device which has been widely adopted in electronics industries. Flash memory may be used to store large quantities of voice, image data and other date in information appliances such as a computer, a cellular phone, a PDA, a digital camera, a camcorder, a voice recorder, an MP3 player, a handheld PC, a game machine, a facsimile, a scanner, a printer, and the like.
In the meantime, in an effort to meet the continuing demand for highly integrated memory devices, research has focused on the development of nonvolatile memory devices (hereinafter, referred to as a three-dimensional nonvolatile memory devices) where memory cells are arranged in three-dimensions. However, due to relatively large loads attendant three-dimensional nonvolatile memory devices, challenges are encountered in the realization of devices exhibiting high operating speeds.